INFRARED SPECTROSCOPIC STUDIES OF CO2 SORBED IN GLASSY AND RUBBERY POLYMERIC MEMBRANES

Infrared spectra of CO2 sorbed in rubbery and glassy polymers were mea sured to examine the relationships between the spectroscopic data and physical properties of the polymeric membranes. The ''V-shape'' tenden cy in the plot of W1 [ i.e., half-width of CO2 peak sorbed in the memb ranes] vs glass-transition temperature (T(g)) is observed, and has exa ctly the same tendency that is widely known from the plot of log D (di ffusion coefficient) vs T(g). It is suggested that the membranes havin g a wider W1 give a faster diffusion coefficient, since W1 is inversel y related to the moment of inertia of CO2 in the membranes. Two distin ct peaks of CO2 were not observed in the infrared spectra of CO2 sorbe d in the glassy polymers. This suggests that the states Of CO2 in the Henry mode and Langmuir mode in the glassy polymers are similar in the spectroscopic measurements. (C) 1994 John Wiley & Sons, Inc.